You can play pvp if you want, you just have to make sure the map is set up correctly. The map owner can change to pvp in the settings, but the default is pve. Most players that I know prefer to avoid pvp though and would rather play co-op with others, but there have been public pvp servers in the past.

And there are more than 2 players a day, the longest running friendly server has on average 50 visitors per day!